Wobbliness (ataxia) after Fenbendazole in cats

22 reports to the FDA describe wobbliness (ataxia) in cats given Fenbendazole. That is 7.7% of all reports for this medicine, compared with 4.7% across reports for all cat medicines, so it is reported unusually often with this medicine.

22Reports
55%Marked serious
4.5%Recovered
18%Died or euthanised
Same dayTypical onset
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How soon it started

Same day
8 62%
1–2 days
4 31%
3–7 days
1 7.7%
1–4 weeks
0 0.0%
Over a month
0 0.0%

How the animals did

Recovered
1 4.5%
Still unwell when reported
4 18%
Died
2 9.1%
Euthanised
2 9.1%
Not known
13 59%

Problems reported at the same time

Tremors
7 32%
4 18%
Nystagmus
4 18%
Kidney problems
3 14%

Age of the animals

Under 1 year
7
1–3 years
5
4–7 years
7
8–11 years
2
12+ years
1

About this medicine

Fenbendazole treats intestinal worms and some other parasites.

Questions owners ask

Can Fenbendazole cause wobbliness (ataxia) in cats?
22 reports link the two, but a report alone does not prove the medicine was the cause: other illnesses, other medicines or coincidence can be involved. Your vet can judge it for your animal.
How soon after a dose was it reported?
In half of the reports with dates, it started within the same day of the first dose.
What should I do?
Don't give another dose until you've spoken to your vet, and keep the packaging so you can tell them the product and dose. Your vet can also report it to the FDA (or you can, through the manufacturer or FDA form 1932a).

Wobbliness (ataxia) with similar medicines

All reported side effects of Fenbendazole in cats · Medicines most reported with wobbliness (ataxia)